IL-17 affects the immune regulation of CD4+ T cells in dilated cardiomyopathy through JAK/STAT pathway.

Purpose: Studying the effect of interleukin-17 (IL-17) on the mechanism of CD4+ T-cell immune regulation and the Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway may offer new ideas and methods for the therapy of dilated cardiomyopathy.

Methods: Naive CD4+ T cells were isolated from mice using a magnetic bead sorting reagent and manipulated by overexpression or knockdown of IL-17. Protein levels of Janus kinase 2 (JAK2), phosphorylated JAK2 (p-JAK2), signal transducer and activator of transcription 3 (STAT3), phosphorylated STAT3 (p-STAT3), matrix metalloproteinase-2 (MMP-2), and matrix metalloproteinase-9 (MMP-9) were determined by Western blotting. Quantitative polymerase chain reaction was used to assess the levels of JAK2, STAT3, MMP-2, and MMP-9. Expression of tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), interleukin-4 (IL-4), and interferon-gamma (IFNγ) was determined by enzyme-linked immunosorbent assay test kits. TNF-α, IL-1β, IL-4, and IFNγ secretion was measured by flow cytometry.

Results: In CD4+ T cells, IL-17 overexpression increased TNF-α, IL-1β, IL-4, IFNγ, p-JAK2, p-STAT3, MMP-2, MMP-9 levels, and apoptosis. Knockdown of IL-17 reduced the levels of TNF-α, IL-1β, IL-4, IFNγ, p-JAK2, p-STAT3, MMP-2, and MMP-9, as well as the level of apoptosis.

Conclusion: Through regulation of IL-17 expression in CD4+ T cells, this study reveals its crucial role in regulating the secretion of inflammatory factors, activation of the JAK/STAT signaling pathway, expression of matrix metalloproteinases, and apoptosis of CD4+ T cells.